1. Field of the Invention
The present invention relates to a tub assembly in a drum-type washing machine, in which a bracket fixing a bearing housing is eliminated so that a motor assembly can be installed in an interior space created at the rear of the tub.
2. Discussion of the Related Art
Generally speaking, laundering using a drum-type washing machine is carried out using a frictional force between the laundry and a rotating drum that receives the driving force of a motor. Such a method causes little damage to the laundry, prevents the laundry from getting tangled, and achieves such washing effects as beating and rubbing.
FIG. 1 illustrates a drum-type washing machine according to a related art, in which the motor is installed below the drum.
Referring to FIG. 1, a cylindrical tub 2 made of stainless steel is installed inside a cabinet 1, and a cylindrical drum 3 is rotatably installed inside the tub. A motor 15 is mounted on one lower side of the tub 2, and a motor pulley 151 is connected to the motor. A drum shaft 31 is installed at a rear side of the drum 3, and a drum pulley 32 is installed at the rearward end of the drum shaft. The drum pulley 32 is rotatably coupled, via a belt 16, to the motor pulley 151.
To support the tub 2, a suspension spring 24 is installed between an inner face of an upper side of the cabinet 1 and an upper side of the tub's outer circumference. A friction damper 25 is installed between an inner side of a lower surface of the cabinet 1 and a lower side of the outer circumference of the tub 2, to attenuate shaking of the tub upon dewatering.
The tub 2 consists of a tub cover 21 forming a front part of the tub, a tub body 22 forming a sidewall part of the tub, and a tub back 23 forming a rear part of the tub. The drum shaft 31 is assembled to a bearing housing 4, in which bearings 4a and 4b are installed, and the assembly is fixed to a central portion of the tub back 23.
Three coupling bridges 41 are integrally formed as one piece, with 120° of spacing between the bridges, to radiate outwardly from the bearing housing 4. The outer end of each coupling bridge 41 is fixed to a rear side of the tub body 22, via a fixing bracket 14 and a bolt 8, so as to be assembled to the tub back 23.
A counterweight 26 installed at a front side of the tub 2 counteracts a weight imbalance resulting from the tub back 23 being made of stainless steel and the motor 5 being mounted on its rear side.
The tub 2, which is made of stainless steel, is constructed by welding together the tub cover 21, tub body 22, and tub back 23. Then, the bearing housing 4 is assembled to the tub back 23, and the assembly is completed by coupling the drum shaft 31 and drum pulley 32.
In the above drum-type washing machine, the motor is installed below the tub and rotates the drum using the pulley. Another drum-type washing machine, however, uses a direct-coupled motor mounted on the rear side of the tub.
FIG. 2 illustrates a drum-type washing machine according to a related art, in which a direct-coupled motor is installed at a rear side of the tub, and FIG. 3 illustrates a tub body 22 and a tub back 23. Notably, a coupling structure of the tub back 23 is attached to the rear side of the tub 2.
Referring to FIGS. 2 and 3, the tub back 23 has an outer circumference wall 23a to enclose an outer rim of a tub 2. A rear edge of the tub body 22 is inserted inside the outer circumference wall 23a, and contacting portions are fixed by welding. The tub back 23 is welded to the periphery of the rear side of the tub 2, thereby enclosing the tub.
A motor assembly 6 is coupled to the tub back 23 at the center of a rear surface thereof. Specifically, the motor assembly 6 is coupled with the tub body 22 by a bearing housing 60 using a fixing bracket 62. The bearing housing 60 and fixing bracket 62 are radially installed at the 120° points with respect to the centrally installed motor assembly.
A plurality of bridges 61 radiate from the center of the bearing housing 60, with each bridge fixed to a periphery of the tub back 23. Specifically, each bridge 61 is coupled to a surface of the tub 2, either by welding or by a coupling member 62a, e.g., a bolt, such that the tub body 22, tub back 23, and bearing housing 60 are all fixed to the tub.
In the drum-type washing machine as shown in FIGS. 2 and 3, the tub back 23, having a diameter greater than that of the tub body 22, is attached to the rear side of the tub body, and the bracket 62 for assembling the tub body 22, tub back 23, and bearing housing 60 is also fixed to the rear side of the tub body 22, such that the congregate size and weight of the rear side of the tub assembly increases accordingly, which directly affects the size and weight of the drum-type washing machine as a whole. As a result, the manufacture of such a large and heavy product is cumbersome, the welding the fixing bracket 62 for fixing the tub back 23 and bearing housing 60 is time-consuming, and the overall product cost is increased to compensate for any inadequate welds.